The present invention relates to a golf club head in which a metallic face body is press-fitted into a recess formed on a ball hitting surface of a face section of a metallic head body. Also, the present invention relates to a method of manufacturing the golf club head.
The above golf club head and the method of manufacturing the golf club head are disclosed, for example, in Japanese Unexamined Patent Publication Nos. 5-337222 and 6-182006.
In the golf club head disclosed in Japanese Unexamined Patent Publication No. 5-337222, on the inner circumferential surface of the recess formed on the ball hitting surface of the face section of the metallic head body, there is provided a dented section composed of a linear inclined surface protruding outward as it comes from the opening edge of the recess to the rear surface of the head body. In the above dented section, at a position closest to the rear surface of the head body, there is formed a bottom section protruding inward from the opening edge.
When the conventional golf club head is manufactured, the metallic face body is press-fitted into the recess of the head body. Due to the foregoing, a portion close to the outer edge portion of the inserting end of the face body is plastically deformed along the bottom section of the recess. When the inserting end of the face body enters the recess in this way, the metallic face body can be engaged with the recess.
In the golf club head disclosed in Japanese Unexamined Patent Publication No. 6-182006, on the inner circumferential surface of the recess formed on the ball hitting surface of the face section of the metallic head body, there is provided a dented section including an engaging section once dented outward from the opening edge of the recess and a perpendicular extending section which extends substantially perpendicularly to the ball hitting surface toward the rear surface of the head body. Further, in the above dented section, at a position closest to the rear surface of the head body, there is provided a bottom section protruding inward from the opening edge. Furthermore, in a portion close to the outer edge of the inserting end of the metallic face body press-fitted into the recess of the head body, there is provided a protrusion which protrudes substantially perpendicularly to the ball hitting surface of the face body.
In the case of manufacturing the conventional golf club head, when the metallic face body is press-fitted into the recess of the head body, a protrusion in the portion close to the outer edge at the inserting end of the face body is plastically deformed in such a manner that the protrusion is bent along the bottom section of the recess. In this way, the protrusion enters the recess so as to attain the engagement with the recess.
In the golf club head disclosed in Japanese Unexamined Patent Publication No. 5-337222, a portion close to the outer edge of the inserting end of the face body enters the dented section in such a manner the portion is plastically deformed along the bottom section of the recess of the head body. First, this portion close to the outer edge of the inserting end of the face body fills a region in the recess close to the bottom section which is most distant from the opening end of the recess. Then, the portion comes toward the opening edge along the inner circumferential surface of the recess. When the portion gradually comes inward, it comes close to the opening edge. In this way, the portion close to the outer edge of the inserting end of the face body fills the residual region of the dented section. The portion close to the outer edge of the inserting end of the face body, which has been plastically deformed along the bottom section of the recess of the head body, finally reaches a region close to the opening edge of the recess in the process of the above plastic deformation. Accordingly, blowholes tend to occur in a region close to the opening edge of the recess. When a large number of blow holes are generated, an abnormal sound is caused in the case of hitting a golf ball with the ball hitting surface of the face body. Further, there is a possibility that the original performance of the face body can not be exhibited and the face body comes off from the recess of the head body. For the above reasons, when a large number of blow holes are found in the above region in the process of final inspection conducted in the process of manufacturing the golf club head, the golf club head is thrown into the discard.
In the golf club head disclosed in Japanese Unexamined Patent Publication No. 6-182006, a protrusion in the portion close to the outer edge of the inserting end of the face body is plastically deformed and fed into the above dented section along the protrusion in the recess of the head body. Accordingly, the mechanical strength of the protrusion, which has been plastically deformed, is so low that the engaging strength of the face body with respect to the recess of the head body is low. When the protrusion is previously formed in the portion close to the outer edge of the inserting end of the face body, it requires a complicated work in the process of manufacturing the golf club head.